104二叉树最大深度

code

/**
 * Definition for a binary tree node.
 * function TreeNode(val, left, right) {
 *     this.val = (val===undefined ? 0 : val)
 *     this.left = (left===undefined ? null : left)
 *     this.right = (right===undefined ? null : right)
 * }
 */
/**
 * @param {TreeNode} root
 * @return {number}
 */
var maxDepth = function(root) {
    let result = 0;
    function traverse(root, depth){
        if(root === null){
            return;
        }
        result = Math.max(result, depth);
        traverse(root.left, (depth + 1));
        traverse(root.right, (depth + 1));
    }
    traverse(root, 1);
    return result;
};

总结

1. 说来好像也没啥，类似层序遍历那种的，记录下长期状态
2. 我觉得没啥问题